Dropout fuse construction



May 15, 1951 s. l. UNDELL 2,553,098

DROPOUT FUSE CONSTRUCTION Filed Oct. 29, 1948 4 Sheets-Sheet l @WMI . i 1, 11. N Wn N gli S. l. LINDELL DROPOUT FUSE CONSTRUCTION May 15, 1951'A Flled Oct 29 1948 May 15, 1951 s. l. LINDELL.

DROPOUT FUSE CONSTRUCTION 4 Sheets-Sheet 3 Filed Oct. 29. 1948 May 15, 1951 s. l. LINDELL DRoPouT FUSE coNsTRUcTroN 4 Sheets-Sheet 4 Filed Oct. 29. 1948 Patented May 15, 1951 UN ITE-1D .STATES PATENT OFFICE DRoeoU'r Foss coNs'rRUofrroN .Sigurd I. Lindell, Chicago, Ill., assigner to S & C Electric Company, Chicago, Ill., a corporation of Delaware Application October 29, 1948, Serial No. 57,347

(Cl. 20D-114) 14 Claims. l

This invention relates to dropout 4fuse conn struc-tions. Ithas particular relation to improve- .ments in the dropout fuse constructionshown in Patent No. 2,328,818 which is assigned to the assigneeof this application.

Among the objects of this invention are: To

.limit .the tension stressYapp-lied tothe fuse link lin ardropout fuse construction in'whichrtherdrop.

out action giseffected by adouble jointed hinge `or toggle'mechanism; to lock the toggle mechasult of the blowingof the vfuse link by impact ,and by spring action in the event that the toggle mechanism should fail to move-or be slow in 'moving to the open position; to combine the locking mechanism and the impact releasing -mechanism; and to construct the dropout, mechanism so that its operation is unhindered subn stantially by corrosion of the moving parts or by sleet and ice.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention isdisclosed in theembodiment kthereof lshown inthe accompanyingdrawings and .it comprisesthe features of construction, com-bivnationof elements and arrangement of parts -whiych will be exemplied in the construction .natura and scope of this invention, reference can behad to the following-detailed description, taken gtogether iwith :the accompanying ydrawings, in -whichl jFigure 1 `isa View,V in side-elevation, of adrop- `out fuse construction in which-this invention-is f-incorporated;

Figure 2 is a View, in -frontelevation, of the dropout fuse construction shown'in Figure l;

Figure -3v` is :a longitudinal, Asectional-view of. the

fuse tubershown in Figures l and "2 and illustratingghow a fuse link is located therein;

Figures f5-and 6 are views, partly in side ele- `vationfandpartly in-sectiOn, 4showing successive stages in the operation of kthe toggle locking` and --releasing mechanism of the present invention;

and

spaced relation.

2 Figures 7, 8, 9.and 10 are perspective views of the elements making up the toggle, v,locking .and releasing mechanism.

Referring now particularly toFiguresl and 2 -of the drawings, it will be observed that the reference character lil designates an insulator which may be supported'by a bracket II from a suitable crossarm or the like. The insulator I0 carries upper and lower line terminals I2 .and AI3 at lits ends. lIt will be understood that Vother vforms of insulation can be provided l-for maintaining the line terminals I2 and kI3 in insulated The upper line terminal I2 carries a .sleet hoodfI i which is pivote'd'at I5 and is urged or biased kdownwardlyabout the pivot 4point Iby a leaf spring I5.

It will be understood that the sleet hood I4 constitutes apart of the contact which isassociated with theupper line terminal I2. lIt iszprovided with a recess i9 in its underside for making `latclfiingcontact engagement with a capiZii that is threaded on the upper end of a fuse tube :12I formed of insulating material in the conventional -nannern Within the fuse tube :2 I there is .afuse link V22 which may beef conventional construction and it is provided with .a iiexible lead kor vcable 23 that, extends out of the lower openend of theifuse tube 2 I. It will be noted that the. cap

,2t isthreaded on the aupper end lof a tubular upper fuse tube terminal Ziandthat it serves to clamp the upper end ofthe'fuse link 22 thereto. yThe upper fuse tube terminal y2li has aneye 2,5 formed integrally therewith for receiving the prong of `a switch stick for operating the -iuse tube 2 I to thecircuit closed position.

As indicated, the iieXible lead `or cable ,23 Iof the fuse link 2.2 extends out-of the lower en d of the fuse tube 2l. It is passed around a stud 28 which projects from -a toggle member 29 that is shown more clearly inv Figure 7 of .the drawings. A clamp nut 3G threaded on the' stud 28,-serves to holdthe exible lead or cable'2f3 indgood contact engagement with the toggle member 29.

The toggle member 29 constitutes a double pivot mounting for the fuse tube2 I. It ispivoted `at 3i between akfpair of arms 32 which extend .rearwardly from a tubular metallic tting 33 thatis fastened to the-lower end ofthe vfuse tube 2|. It will be noted that the toggle member 29 has an integrally formed eye 35.1or receiving the prong of va switch stick for placing the fuse tube in position on the lower line terminal I3.

The second pivot furthe toggle member 29 is provided by trunnions Bti-whichextend from -opposits-sides thereof Aasshown in Figure 7. The

'attacca trunnions 38 are rockably mounted in slots 39 located in a support member 40 which, as shown1 may form a part of the lower line terminal I3. It will be understood that the support member d, in some cases, may be independent of the lower line terminal I3. For illustrative purposes, however, it is shown in the drawing as being an integral part of the lower line terminal I3. Good electrical connection is provided between the toggle member 29 to which the flexible lead or cable 23 is clamped and the support member 40 by rearwardly projecting contact members 4|, Figure 5, on the toggle member 29 which engage spring Contact ngers 42 that are carried by the support member 46. It will be` understood that other contact arrangements can be provided for interconnecting the toggle member 29 and the lower line terminal I3.

It will be understood that the leaf spring I6 or the equivalent biasing means commonly used in this type of device urges the sleet hood I4 downwardly. This biasing force is applied to the cap 2|) at the upper end of the fuse tube 2| and, together with the force of gravity, serves to bias the fuse tube 2| downwardly for rocking movement about the axis through the pivotal connection 3| and also about the axis through the trunnions 38. The force of the spring I6 acts on the fuse tube 2| and a component of it acts to break the toggle joint of which the toggle member is a part. It will be noted that the broken line 43, which extends through the cap 20 or point of application of this force and the axis through the trunnions 38, is slightly to the left of the pivot axis 3| so that the toggle member 29 is positioned slightly in advance of the center position rather than being positioned beyond the center position. Thus the toggle member 29 does not have to move past the center position in rocking to lower the fuse tube 2| from the closed position shown in Figure 1 and unlatch it from the sleet hood |4 to permit it to swing to the open position.

The iiexible lead or cable 23 extends over a flipper 4G which is shown more clearly in Figure 9 of the drawings. The ilipper 46 is rockably mounted on a pin or shaft 4l, Figure 8, which extends through the trunnions 38. Thus, the flipper 46 is pivoted preferably to the toggle member 29 about the same axis that it is pivotally mounted on the support member 4|). The outer end 48 of the flipper 46 is bifurcated for receiving the flexible lead or cable 23 and it is provided with a groove 49, Figure 3, on its underside through which the ilexible lead or cable 23 extends for anchoring about the stud 28.

` A tooth or detent E), Figure 4, extends rearwardly and downwardly from the tubular metallic fitting 33 at the lower end of the fuse tube 2|. The front face 5| of the tooth or detent 5i) is arranged to engage a face 52 of a detent 53 which is formed integrally with the iiipper 46. This arrangement of the faces 5| and 52` takes place when the fuse link 22 is installed in the fuse tube 2| as illustrated in Figures 1 and 3 of the drawings. In this position the plane of engagement of the faces 5| and 52 extends generally parallel to the broken line 43 and transversely of the longitudinal axis of the flipper 46 which, as shown in Figure 1 in the closed position of the dropout fuse, extends transversely of the longitudinal axis of the fuse tube 2|. Since the faces 5| and 52 engage in a plane which is generally at right angles to the longitudinal axis of the flipper 45, relative movement between these faces through a slight extent is permitted as a result of stretching of the flexible lead or cable 23 without releasing the locking engagement provided by the detents 50 and 53 which engagement prevents the toggle member 29 from swinging away from the fuse tube 2|. Because of the provision of the detents 55 and 53 which prevent 'the unlocking of the toggle member 29, and the lever ratios of the parts making up the toggle joint including the flipper 46, the force exerted by the leaf spring I6 and any other downward force exerted on the fuse tube 2| is transmitted only to a very minor extent to the fuse link 22. Since these forces ultimately are applied to the flexible lead 23 only to a very small degree because of the lever ratios involved, there is sub stantially no likelihood that the fuse link 22, particularly the low current links which are relatively weak mechanically, will be broken during the closing movement of the fuse tube 2 I.

The lock for the toggle mechanism provided by the detente 55 and 53 is located so as to act at right angles to the toggle member 23 and close to the axis through the trunnions This permits the positioning of the axis 3| ahead of the center position represented by the broken line 43 and thus facilitates breaking of the toggle when the fuse link 22 blows. It also permits some rocking movement of the ipper 4i; on stretching of the flexible lead 23 without materially efecting a shift in the position of the axis 3| and thereby changing the lever ratios of the toggle mechanism. At the same time there is a minimum of force transmitted through the toggle mechanism and flipper 46 to the fuse link 22 and thus there is little likelihood of its being broken even when a link of the lowest ampere rating is employed.

The tension which is applied to the fuse link 22 is limited substantially to that which is exerted by a coil spring 54 which is shown more clearly in Figure 110. The coil spring 54 has a central reverse bend section 55 which interfits with the detent 53, as shown in Figure 5. Also the spring 54 has hook ends 55 which engage with anges 51, Figure 7, on the toggle member 29. The spring 54 acts between the toggle member 29 and the ilipper 46 and serves on low current faults to withdraw the exible lead or cable 23 after blowing of the fuse link 22. This serves to extinguish very quickly any are which may be drawn within the fuse tube 2| and particularly arcs which are drawn as a result of operation of the fuse link 22 on low fault currents. The spring 54 also assists in breaking the toggle joint as will be pointed out presently.

It sometimes happens that, as a result of frictional resistance caused by corrosion or sleet, the toggle member 2e may fail t0 rock about the trunnions 38 when the fuse link 22 blows. When this occurs the fuse tube 2| remains in place between the terminals I2 and I3 and thus does not provide the air gap in the circuit which is desired to prevent leakage over the fuse tube 2| by its dropping out of contact engagement with the sleet hood I4.

With a view to insuring that the toggle member 29 does rock about its trunnions 38 so as to lower the fuse tube 2| and drop the cap 25 from engagement with the recess I5, an anvil member 60 Ais provided by the rear face of the tooth or detent 50. This anvil member 6G is arranged to be engaged by a hammer member 6| which constitutes an integral extensi-on of the flipper 46. Ends 62, Figure 9, of the hammer member 6I engage flanges'EB, Figure 6', formed integrally with the toggle member 29 to limit the relative movement between theipper 46 and the toggle member 29. In addition to the impact against the anvil member 60 by the hammer member 6| resulting from the kinetic energy of the ipper 46, the spring 54y acts in the same direction since it has not yet been completely unloaded. Sufficient force is exerted by the flipper 46 and the spring 54 to move the toggle member 29 under conditions most likely to be encountered in practice.

It will be noted that the hammer member 6I is positioned fairly close to the axis of rotation of the flipper 46. The center of gravity ofthe flipper 43 and the pointV of application of the force exertedby the spring 54-are spaced substantially further away from this axis. Further, the point of contact of the hammer member 6| with the-anvil member 60 is along the line joining the axis- 3| and the axis of the trunnions .38. Accordingly, the pry out action of the kinetic energy in the flipper 46 and of the springy 54 is increased by this construction.

As shown in Figure 6, the metallic fitting 33 has a rearwardly extending projection 64 from which the tooth or detent 50 projects. The projection 64 has a rear face 65 which abuts faces 66, Figure 7, of the toggle member 29. This fixes the position of the-toggle member 29 in relation to the metallic fitting 33 and fuse tube 2|. These faces 65 and 66 are held in engagement by the detents 5E! and 53 when their faces 5| and 52 are Iin engagement.

The fuse link 22 is inserted in the fuse tube 2| when the latter is removed from its operative position on the upper and lower line terminals I2 and I3. The fuse link 22 is 'inserted through the upper open end of the fuse tube 2| when the cap is removed. Thereafter the cap 20 is screwed into place as shown in Figure 3 for holding the fuse link in positionfin the fuse tube and its upper end incontact enga'gement with the upper fuse tube terminal 24. The flexible lead or cable 23 extends out of the lower open end of thefuse tube 2|. Next the ipper 46 is swung to the position shown in Figure 1 of the drawings, the spring 54 is tensioned further, and the flexible lead or cable 23 is trained thereover and is passed around the stud 28. Then the clamp nut is tightened to hold the flexible lead or cable 23 in good contact engagement with the toggle member 29.

When the fuse link 22 is installed as just described, the faces 5I and 5-2'of the detents 5D and 53 respectively are in engagement. Also, the faces65 and 66 of the projection 64 and the toggle member 29 are in engagement. It is this locking engagement between the detents and 53 which prevents the toggle member 29 from swinging away from the fuse tube 2| and holds the faces and 66 in engagement. The nexible lead or cable 23 may stretch somewhat and permit the flipper 46 to rotate slightly about the pin or shaft 41. The faces 5| and 52 of the detents 5t and 53 remain in contact engagement although they move slightly relative to each other. The toggle member 29 'is moved through an insignificant extent and the faces 65 and 66 separate only slightly. The pivot point 3| remains substantially in its original position and thus there isno substantial change in the lever ratios of the toggle'mechanism even though thev flexible lead 23 hasstretched some 6. what. This construction permits the toggle mechanism to be designed to have measured positive leverage so as to facilitate its being broken after the fuse link has been blown. Breakage of fuse links and failure of the toggle mechanism to release due to the placing of the axis too close to the center position along the line 43 are avoided. Also there is a positive sequence in operation since the toggle mechanism cannot break prematurely suiiiciently to permit contact to be broken between the cap 20 and hood I4 but it can break to this extent only after the ipper has swung to move the flexible lead 23 and extinguish the arc.

The fuse tube 2| is placed in operative position with respect to the line terminals I2 and I3. In order to do this the prong of a switch stick is inserted in the eye 35 and the trunnions 33 are inserted in the slots 33 of the support member 49. Thereafter, the prong of the switch stick is removed from the eye 35 and inserted in the eye 25. The operator then swings the fuse tube 2| to the position shown in Figure l where the cap 29 engages the recess I3 in the sleet hood Irl. When the fuse tube 2| is swung to the closed position, it is subjected to a substantial downward thrust as a resultof this movement and the action ofthe spring I6. However, this thrust is applied to the fuse link 22 in a greatlydiminished value because of the lever ratios involved and since the faces 5| and 52 of the detents 50 and 53 are in Contact and serve, as above described, to resist thrust tending to rock the toggle member 29 away from the fuse tube 2|.

In Figure 4 of the drawings the action of the present invention is illustrated immediately after the fuse link 22 has-blown and the remaining portion of the flexible lead or cable 23 is being Withdrawn from the fuse tube 2 In this showing the fuse tube 2| has not moved. Thus the pivot axis 3| and the axis of the pin or shaft 4'! remain stationary. Since the iiipper 56 is no longer restrained by the fuse link 22, it is swung in a clockwise direction by the spring 54. Sin-ce the spring 54 reacts against the toggle member 29 while swinging the flipper 4G, the former. is held thereby in its initial position. The face 521 of the detent 53 on the flipper 45 moves out of engagement with the face 5| on the tooth or detent 59. As a result, the fuse tube 2| is free to swing downfand away. from the upper line ter.- minal I2 together with the toggle member 2S. However, the circuit has been interrupted and any arc incident thereto has beenvdrawn and ex-` tinguished within the fuse tube 2|. There is then no arcing between the cap 2| and the sleet hood I4 when they separate.

It may be the case that the toggle member 29 is restrained by corrosion or sleet from movement which would effect the lowering and swinging out movement of the fuse tube 2|. In order to overcome such resistance to movement of the toggle member 29, the anvil member 39 is im pacted by the hamm-er member 6i when the flipper 46 has rocked to theposition shown in Figure 5. By this time it has acquired considerable momentum and, as a result, the hammer member 6| strikes the anvil member 6U a blow which together with the remaining tension of the spring 54 is sufficient to cause the lower end of the fuse tube 2| and the toggle member 29 to swing outwardly, the latter about the axis through its trunnions 38. As pointed out before these forces act on the anvil member 66 close to the axis of the ipper'46 and thus are highly effectivel in pry-.-

ing out the detent G and the lower end of the fuse tube 2l. The continued rocking movement of the iiipper i6 is finally arrested when the ends 62 engage the iianges G3 of the toggle member ZS. The toggle member 2Q then continues to rock about the airis of the trunnions 38. This movement of the toggle member fili lowers the pivot axis 3l of the fuse tube 2i and the net result is to lower the fuse tube Zi away and disengage its cap 2G from the sleet hood lil, thereby permittingl it to swing outwardly away from the upper line terminal i2.

The toggle member 2Q overlies the flipper ifi and, therefore, the likelihood of the latter being prevented from operating in the manner described by sleet is minimized.

Since certain changes can be made in the fore-- going construction and diierent embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drany ings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

l. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, a flipper pivoted on said toggle member and adapted to be restrained by said fuse link, a spring biasing said flipper for withdrawing from said fuse tube the portion of said fuse link released on blowing thereof, a detent stationarily mounted on the lower end of said fuse tube, and a detent on said flipper for engaging said detent on said fuse tube as long as said flipper' is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents.

2. In a dropout fuse construction wherein a i fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, a flipper pivoted on said toggle member and adapted to be restrained by said fuse link transversely of said fuse tube, a spring biasing said flipper for withdrawing from said fuse tube the portion of said fuse link released on blowing thereof, a detent on the lower end of said fuse tube, and a detent on said flipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said iuse tube is restrained by said detents, the engaging faces of said detents being located in a plane transverse to said nipper whereby limited relative movement of said faces can take place on stretching of said fuse link without materially increasing the force required to be exerted by said fuse link in opposition to said force acting to rock said toggle member.

3. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, a flipper pivoted on said toggle member about the same axis that it is pivoted on said support means and adapted to be restrained by said fuse link, a spring biasing said flipper for withdrawing from said fuse tube the portion of said fuse link released on blowing thereof, a detent stationarily mounted on the lower end of said fuse tube, and a detent on said ipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents.

4. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, a flipper pivoted on said toggle member about the same axis that it is pivoted on said support means and adapted to be restrained by said fuse link transversely of said fuse tube, a spring biasing said flipper for withdrawing from said fuse tube the portion of said fuse link released on blowing thereof, a detent on the lower end of said fuse tube, and a detent on said flipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents, the engaging forces of said detents being located in a plane transverse to said flipper whereby limited relative movement of said faces can take place on stretching of said fuse link without materially increasing the force required to be exerted by said fuse link in opposition to said force acting to rock said toggle member.

5. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, fastening means on said toggle member for connecting one end of said fuse link thereto, a flipper pivoted on said toggle member and adapted to have said fuse link trained thereover, a spring reacting between said toggle member and said 'iipper for biasing the latter to withdraw from said fuse tube the portion of said -4 fuse link released on blowing thereof, a detent stationarily mounted on the lower end of said fuse tube, and a detent on said flipper for engaging said detent on said fuse tube as long as said ipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents.

6. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lowervline terminal having support means associated therewith, vin combination, :a toggle member-for pivoting onl saidsupport means .and on the lower nendof ysaid fuse tube for lower,-

ng it to disengage said latch. means and permit saidfuse tube toswing downwardly to open circuit position, fastening means on said toggle member for connecting one end of said fuse link thereto, a flipper pivoted on said toggle member about the same axis that it is pivoted on said support means and adapted to have said fuse link trained thereover, to hold it transversely of said fuse tube, a spring reacting between said toggle member and said flipper for biasing the latter to withdraw-from said fusey tube the portion of vsaid fuse link releasedon blowing thereof, a'detent on the lower endofsaid fuse tube, and a detent on said ilipper for engagingr said detent on said fuse tube as long as said ipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents, the engaging faces V`of said detents being located in a plane transverse to said flipper whereby limited rela tive movement of said faces can take place on stretching of said fuse link without materially increasing the force required to be exerted by said fuse link in opposition to said force acting to rock said toggle member.

7 In a dropout fuse construction wherein a fuse tube containing a fuse linkis held by latch means to interconnect upper and lower line terminals, said ,lower line terminal having support means associated therewith, `in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, a flipper pivoted on said toggle member and adapted to be restrained by said fuse link, a spring biasing said flipper for withdrawing from said fuse tube the portion of said fuse link releasedon blowing thereof, a detent on the lower end of said lfuse tube, a detent on said iiipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents, an anvil member on the lower end of said fuse tube, and a hammer member on said flipper arranged to strike said anvil member when said flipper is released on blowing of said fuse link to rock said toggle member away from said fuse tube for lowering it.

8. The invention, as set forth in claim 7, wherein a tooth is carried by the fuse tube at its lower end to constitute the rst mentioned detent and the anvil with the side adjacent said fuse tube being engaged by the detent on the flipper and the opposite side being engaged by the hammer member.

9. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, a ilipper pivoted on said toggle member and adapted to be restrained by said fuse link transversely of said fuse tube, a spring biasing said flipper for withdrawing from said fuse tube the portion of said fuse link released on blowing thereof, a detent on the lower end of said fuse tube, a detent on said flipper for engaging said detent on said fuse tube as long as said yipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents, the engaging faces of said detents being located in a plane transverse to said flipper whereby limited relative movement of said faces can take place on stretching of said fuse link without materially increasing the force required to be exerted by said fuse link in opposition to saidvforce acting to rock said toggle member, an anvil member on the lower end of said fuse tube, and a hammer member on said ipper arranged to strike said anvil memberwhen said flipper is released on blowing of said fuse link to rock said toggle mel ber away from said fuse tube for lowering it.

10. In a dropoutfuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line ter- `minals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open cir cuit position, a flipper pivcted on said toggie member about the same axis that it is piyoted on said support means and adapted to be restrained by said fuse link, a spring biasing said flipper for withdrawing from said fuse tube the portion of said fuse link released on blowing thereof, a detent on the lower ond cf fuse tube, a detent on said flipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents, an anvil member on the lower end of said fuse tube, and a hammer member on said iiipper arranged to strike said anvil member when said flipper is released on blowing of said fuse link to rock said toggle member away from said fuse tube for lowering it.

11. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for low-- ering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, a flipper pivoted on said toggle member' about the same axis that it is pivoted on said support means and adapted to be restrained by said fuse link transversely of said fus' tube, a spring biasing said. flipper for withdrawing from said fuse tube the portion of said fuse link released on blowing thereof, a detent on the lower end of said fuse tube, a detent on said flipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is applied to said detents, the engaging faces of said detente being located in a plane transverse to said flipper whereby limited relative movement of said faces can take place on stretching of said inse link without materially increasing the force required to be exerted by said fuse link in opposition to said force acting to rock said toggle member, an anvil member on the lower end of said fuse tube, and a hammer member on said ilipper arranged l1 to strike said anvil member when said flipper is released on blowing of said fuse link to rock said toggle member away from said fuse tube for lowering it.

12. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line terminals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, fastening means on said toggle member for connecting one end of said fuse link thereto, a ipper pivoted on said toggle member and adapted to have said fuse link trained thereover, a spring reacting between said toggle member and said iiipper for biasing the latter to withdraw from said fuse tube the portion of said fuse link released on blowing thereof, a detent on the lower end of said fuse tube, a detent on said flipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents, an anvil member on the lower end of said fuse tube, and a hammer member on said flipper arranged to strike said anvil member when said flipper is released on blowing of said fuse link to rock said toggle member away from said fuse tube for lowering it.

13. In a dropout fuse construction wherein a fuse tube containing a fuse link is held by latch means to interconnect upper and lower line teri minals, said lower line terminal having support means associated therewith, in combination, a toggle member for pivoting on. said support means and on the lower end of said fuse tube for lowering it to disengage said latch means and permit said fuse tube to swing downwardly to open circuit position, fastening means on said toggle member for connecting one end of said fuse link thereto, a ilipper pivoted on said toggle member about the same axis that it is pivoted on said support means and adapted to have said fuse link trained thereover to hold it transversely of said fuse tube, a spring reacting between said toggle member and said flipper for biasing the latter to withdraw from said fuse tube the portion of said fuse link released on blowing thereof, a detent on the lower end of said fuse tube, a detent on said flipper for engaging said detent on said fuse tube as long as said flipper is restrained by said fuse link whereby force acting to rock said toggle member and lower said fuse tube is restrained by said detents, the engaging faces of said detents being located in a plane transverse to said iiipper whereby limited relative movement of said faces can take place on stretching of said fuse link without materially increasing the force required to be exerted by said fuse link in opposition to said force acting to rock said toggle member, an anvil member on the lower end of said fuse tube, and a hammer member on said ipper arranged to strike said anvil member when said flipper is released on blowing of said fuse link to rock said toggle mem ber away from said fuse tube for lowering it.

14. The invention, as set forth in claim 13, wherein a tooth is carried by the fuse tube at its lower end to constitute the first mentioned detent and the anvil with the side adjacent said fuse tube being engaged by the detent on the iipper and the opposite side being engaged by the hammer member.

SIGURD I. LINDELL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,324,114 Schultz et al July 13, 1943 2,328,818 Lindell et al Sept. 7, 1943 

